Sam Loyd's Juggler Puzzle

The clown after juggling with the five triangular pieces of cardboard to attract attention proceeds to cut one of them into two pieces.

He then lays the six pieces upon the top of the box and shows that they will fit together and form a perfect square.

The pieces represent five right-angled triangles, say one inch high by two inches on the base, so you can readily cut five similar pieces from paper and then guess how to cut one of them so that the six pieces will form a perfect square.